Pressure lid container

ABSTRACT

Pressure lid can or container with an at least one-part body member and a lid member, which together with the closure-side end of the body member forms a tight closure, in which a lever gap is left free between the body member and the lid member for the engagement of a lever enabling the lid member to be levered up and in which the lid member has an all-round, resilient engagement lip, which engages from the inside under pretension in a closure crease of the body member adapted to the engagement lip shape (according to patent application P 40 29 146.4), in which instead of the engagement lip of the lid member engaging in a separately produced closure crease, it resiliently engages below an inwardly rolled, upper circumferential edge bead of the body element.

This application is a continuation-in-part of U.S. patent applicationSer. No. 856,057, filed May 8, 1992.

FIELD OF THE INVENTION

The invention relates to a pressure lid can or container with an atleast one-part body member and a lid member, which together with theclosure-side end of the body member forms a tight closure, in which alever gap is left free between the body member and the lid member forthe engagement of a lever enabling the lid member to be levered up andin which the lid member has an all-round, resilient engagement lip,which engages from the inside under pretension in a closure crease ofthe body member adapted to the engagement lip shape. Such a pressure lidcan or container is the subject of co-pending U.S. patent applicationSer. No. 865,057, the disclosure of which is incorporated herein byreference.

SUMMARY AND OBJECTS OF THE INVENTION

The the foregoing pressure lid container makes it possible in anadvantageous manner to resiliently engage the lid member in the closurecrease of the body member, so that the lid member can be kept underpretension in the closure crease plane, in that the engagement lippresses with spring tension into the closure crease. The essentialadvantage of such a closure is that such a pressure lid container can beopened easily and in non-destructive manner without using any specialtool, in that by engaging a lever in the lever gap, the engagement lipis drawn radially inwards, whereas the body element is pressed outwards,so that the engagement lip is disengaged from the closure crease in thevicinity of the lever. An extremely good seal can be obtained throughthe engagement of the closure with high spring tension. Anotherimportant advantage is that the pressure lid container can be reused, sothat it can be employed in the form of a multiuse pack.

The problem to which the present invention is directed is to the furtherdevelopment of the foregoing pressure lid container with a lid closurewhich can be levered up, so that while retaining all the aforementionedadvantages, in particular, the production of the body member issimplified and the filling and closing of the container are optimized.

According to the invention this problem is solved in that, instead ofthe engagement lip of the cover member engaging in a separately producedclosure crease, it resiliently engages below an inwardly rolled, uppercircumferential edge bead of the body element.

This measure makes it possible to use the upper circumferential edgebead which is normally present on all container body members (providedthat the bead is inwardly rolled) directly as the closure element forthe novel pressure lid container according to U.S. patent applicationSer. No. 865,057 without having to make a separate closure crease forthis purpose. In addition, with such a construction, the volume of thecontainer body member can be utilized in an optimum manner for fillingpurposes, because the engagement lip of the lid member engages directlyon the upper circumferential edge of the body member. As is described ingreater detail hereinafter, it is also possible to further optimize thecontainer closure process.

According to a special embodiment of the invention, below thecircumferential edge bead and at a distance essentially corresponding tothe external diameter of the engagement lip, is provided an inwardlyimpressed body crease. This additional body crease makes it possible tosupport the lid member on the side facing the lever application pointduring the opening of the lid and simultaneously prevents anaccidentally excessively deep pressing of the lid into the body memberon closing.

Alternatively to this, below the circumferential edge bead at a distanceessentially corresponding to the external diameter of the engagementlip, the body member diameter is so reduced so that there is a stepoffset into the interior of the body member. This embodiment has theequivalent effect to the aforementioned additional, lower body creaseand is preferred if the body member is a more flat or shallow container,e.g. in the form of a dish or tray.

Preferably a sealant is provided below the circumferential edge bead inthe area in which the engagement lip resiliently engages below the same.The sealant makes it possible to hermetically seal the pressure lidcontainer and with respect to the behaviour of the closed containerduring sterilization, the same advantages are obtained as described inthe the parent to this patent application.

It is particularly preferred if the sealant has a bactericidal finish,e.g. as a result of the addition of ascorbic acid, so as to preventbacteria from penetrating the sealant.

According to another embodiment of the invention the lid member is madefrom plastic. Unlike in the case where the lid member is made from veryfine metal sheeting, here the engagement lip would be rolled from solidmaterial and the material thickness could be greater.

When the lid member is made from plastic, preferably means for reducingan overpressure are incorporated into the container, which convenientlycomprises an integrated, semipermeable overpressure or pressure reliefvalve.

According to another embodiment of the invention, the circumferentialedge bead is so constructed that it cross-sectionally tapers towards itsupper end by bevelling its inner circumferential surface. This isintended to facilitate the pressing in of the lid member during thefirst or repeated closing of the body member, because as a result of thesliding down of the engagement lip on the bevel of the circumferentialedge bead, the latter can be pressed outwards without any significantuse of force.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is described in greater detail hereinafter relative tonon-limitative embodiments and the attached drawings, wherein

FIG. 1 depicts a partial cross-section through the closure area of afirst embodiment of the inventive pressure lid container in the closedstate.

FIG. 2 depicts a partial cross-section through the closure area of asecond embodiment of the inventive pressure lid container in the closedstate.

FIG. 3 depicts a partial cross-section through the closure area of thefirst embodiment of the inventive pressure lid container during theclosing process.

FIG. 4 depicts a similar view to FIG. 3 showing a later stage during theclosure process.

FIG. 5 depicts a diagrammatic cross-sectional view through an inventivelid member with an incorporated pressure relief valve in the sealedstate.

FIG. 6 depicts a view as in FIG. 5 showing the corresponding pressurerelief valve during the escape of expanded gas from the interior of thecontainer.

DETAILED DESCRIPTION

The pressure lid container 1 comprises a cylindrical body member 2,whose upper end constitutes the body element 6. The pressure lidcontainer 1 is closed in this part with a lid member 4, whose engagementlip 8 resiliently engages in the gap between the inwardly rolled, uppercircumferential edge bead 10 of the body element 6 and the inwardlyimpressed body crease 18. The distance between the body crease 18 andthe lower end of the circumferential edge bead 10 essentiallycorresponds to the external diameter of the engagement lip 8, so thatthe latter engages directly below said bead.

Alternatively thereto and as shown in FIG. 2, the engagement lip 8 of alid member 4' can be supported towards the bottom on a step 20, which isformed in that the diameter of the body member 2 is reduced at adistance which also substantially corresponds to the external diameterof the engagement lip. This embodiment is particularly preferred if thecontainer is, e.g., shaped as a relatively shallow dish or tray.

For a hermetic sealing of the lid closure in both cases a sealant 22 isprovided between the engagement lip 8 and the gap between thecircumferential edge bead 10 and the body crease 18 or the step 20. Thecover member 4 or 4' and the body member 2 are preferably joinedtogether with the sealant still liquid. A bactericidal finish of thesealant, e.g. with ascorbic acid, can effectively prevent the seal frombeing penetrated by bacteria.

Independently of whether or not a sealant 22 is used, in all cases thelid member 4 or 4' can be reused for reclosing the pressure lidcontainer. Thus, the inventive pressure lid container (like that of theparent to this patent application) can be used on a number of occasions,optionally in the form of a multi-use pack.

FIGS. 3 and 4 show the procedure for the first automated closing of theinventive pressure lid container after filling. For this purpose the lidmember 4 is inserted, initially under pretension, in the closing head 30of a closing apparatus. In this state the lid diameter is reduced tosuch an extent that the engagement lip 8 is located on the entirecircumferential edge of the lid member in the position shown in FIG. 3at a limited distance from the upper end 13 of the circumferential edgebead 10. If the closing head 30 moves further down, the engagement lipand the bevelled, inner circumferential surface 12 of thecircumferential edge bead 10 strike one another and any excess fillingmaterial is then squeezed out.

If the closing head moves still further down, then the circumferentialedge bead 10 is forced outwards over its entire circumference about anaxis roughly located in the vicinity of the body crease 18, firstly bythe engagement lip 8 and subsequently by the corresponding ringextension 32 of the closing head 30 (cf. FIG. 4). When the engagementlip 8 is level with the gap between the circumferential edge bead 10 andthe body crease 18 and, into which the sealant 22 has preferably beenintroduced in the still liquid state, by operating the ejector 34 (whichis supported on the upper end 13 of the circumferential edge bead 10)the closing head 30 moves upwards again and the lid member 4 nowresiliently engages below the circumferential edge bead 10 in the mannershown in FIG. 1 and, together with the plasticizing sealant 22, forms ahermetic closure for the pressure lid container.

If the inventive pressure lid is pressed in as a container closure bythe container filler during the initial filling operation, in the caseof a corresponding lid shaping, the dome space which is free fromproduct can be filled with steam by a lance at the instant of pressingin. The condensation of the steam leads to a vacuum in the container,which draws the lid onto the area of the body element 6 covered by thesealant 22.

When using a lid member 4 or 4', suitable pressure reduction means canbe incorporated for reducing an overpressure resulting from the air orgas in the container during sterilization. FIGS. 5 and 6 show such anintegrated, semipermeable pressure relief valve (a socalled coffeevalve) and its function. When the container is closed withoutoverpressure the diaphragm 42 of the pressure relief valve 40 sealinglyengages on the sealing surface 44 and covers the openings 46 towards thecontainer interior (FIG. 5). If an overpressure is formed in thecontainer (e.g. during sterilization), in the vicinity of the openings46, the diaphragm 42 is raised from the sealing surface 44, so that theexpanding gas can flow from the container interior out of the openings46 and 48. Consequently, the overpressure which has formed in thecontainer interior is reduced.

Although the invention has been described in accordance with preferredembodiments, it will be seen by those skilled in the art that manymodifications can be made within the spirit and scope of the presentinvention, and there is no intention to limit the scope of the presentinvention to any of these embodiments. Rather, the scope of the presentinvention is to be measured by the appended claims.

We claim:
 1. A pressure lid container comprisinga body member and a lidmember, said lid member having an all-around, resilient engagement lipfor engagement with said body member from the inside under pretensionand being insertable into a closure-side end of said body member to forma tight closure therewith, said engagement lip having an axialthickness, said lid member including a portion spaced radially inwardlyfrom said closure-side end of said body member to define a lever gapbetween said body member and said lid member for the engagement of alever to permit said lid member to be levered up, said closure-side endof said body member including an inwardly rolled, upper circumferentialedge bead and an inwardly impressed crease, said upper circumferentialedge bead having an exposed end so that said lever may be leveredagainst it as a fulcrum, said inwardly impressed crease being below saidinwardly rolled, upper circumferential edge bead at a distanceessentially corresponding to the axial thickness of said engagement lipso that, when said lid member is inserted, said engagement lip isengaged between said inwardly impressed crease and said inwardly rolled,upper circumferential edge bead.
 2. A pressure lid container accordingto claim 1, wherein a sealant is provided below the circumferential edgebead in the area with which the engagement lip engages.
 3. A pressurelid container comprising a body member and a lid member,said lid memberhaving an all-around, resilient engagement lip for engagement with saidbody member from the inside under pretension and being insertable into aclosure-side end of said body member to form a tight closure therewith,said engagement lip having an axial thickness, said lid member includinga portion spaced radially inwardly from said closure-side end of saidbody member to define a lever gap between said body member and said lidmember for the engagement of a lever to permit said lid member to belevered up, said closure-side end of said body member including aninwardly rolled, upper circumferential edge bead and an inwardlydirected step, said upper circumferential edge bead having an exposedend so that said lever may be levered against it as a fulcrum, saidinwardly directed step being below said inwardly rolled, uppercircumferential edge bead at a distance essentially corresponding to theaxial thickness of said engagement lip so that, when said lid member isinserted, said engagement lip is engaged between said inwardly directedstep and said inwardly rolled, upper circumferential edge bead.